i have two HDD, each has EFI partition. How do I force ubuntu to install /boot/efi on /dev/sdb2 instead of /dev/sda1

Just like in the title:

I have two HDD (/dev/sda and /dev/sdb) on my PC, each has its own EFI (flags: boot, hidden, esp) partition. How to force ubuntu to install /boot/efi on /dev/sdb2 instead of on /dev/sda1

My setup:

ubuntu@ubuntu:~$   sudo lsblk -o NAME,FSTYPE,SIZE,MOUNTPOINT,LABEL NAME                FSTYPE        SIZE MOUNTPOINT                    LABEL sda                             119.2G                                ├─sda1              vfat          100M                               ESP ├─sda2                             16M                                ├─sda3              ntfs        118.1G                               Acer └─sda4              ntfs            1G                               Recovery sdb                             931.5G                                ├─sdb1              ntfs        481.5G                               Data ├─sdb2              vfat          512M                                ├─sdb3              ext4            5G                                ├─sdb4              swap           32G [SWAP]                         └─sdb5              LVM2_member   150G                                  └─vg_ubuntu-lv_ubuntu                                   100G                                sdc                               7.3G                                └─sdc1              vfat          7.3G /cdrom                        UBUNTU 19_0 ubuntu@ubuntu:~$    

sda is my “factory installed” windows.
sda1 is (Windows boot loader).
My “goal” is to keep sda intact/unchanged via installing linux as follows:

NAME                FSTYPE        SIZE MOUNTPOINT                    LABEL sda                             119.2G                                ├─sda1              vfat          100M                               ESP ├─sda2                             16M                                ├─sda3              ntfs        118.1G                               Acer └─sda4              ntfs            1G                               Recovery sdb                             931.5G                                ├─sdb1              ntfs        481.5G                               Data ├─sdb2              vfat          512M /boot/efi                      ├─sdb3              ext4            5G /boot                          ├─sdb4              swap           32G [SWAP]                         └─sdb5              LVM2_member   150G                                  └─vg_ubuntu-lv_ubuntu                / 

unfortunately, yesterday I messed something up, and I installed ubuntu 19 this way:

NAME                FSTYPE        SIZE MOUNTPOINT                    LABEL sda                             119.2G                                ├─sda1              vfat          100M /boot/efi                     ESP ├─sda2                             16M                                ├─sda3              ntfs        118.1G                               Acer └─sda4              ntfs            1G                               Recovery sdb                             931.5G                                ├─sdb1              ntfs        481.5G                               Data ├─sdb2              vfat          512M                                ├─sdb3              ext4            5G /boot                          ├─sdb4              swap           32G [SWAP]                         └─sdb5              LVM2_member   150G                                  └─vg_ubuntu-lv_ubuntu                / 

I plan to boot into /dev/sdb via changing the order bios’ bootloader.

Any idea what can I do to “achieve” the desired effect?


EDIT:
This question was marked as a possible duplicate of:
How can I reinstall GRUB to the EFI partition?

This is not true. The link above (at least according to my understanding) explains how to move grub from one partition to another, or how to install it from “zero”. With the requirement that the Linux OS is already installed.

My question was about “forcing” the grub onto the correct partition during the installation, not after.

If anything, this question is closer to being a duplicate of:
How do I install Ubuntu to a USB key? (without using Startup Disk Creator)
(just replace “USB key” with “2nd internal HDD“)

Three questions on /boot/efi and /boot mountpoints

My Laptop details: Laptop (HP Omen) has 1 TB SATA Drive and 256 GB NVME drive. Windows 10 came pre-installed. It is UEFI enabled and it has a 260MB EFI system partition for Windows.

I am planning to install Ubuntu 19.04 along with the above Windows 10 installation (Dual boot).

So, I have decided to allocate 350 MB in my NVME drive for /boot/efi — maybe /dev/sda1

Question1. I would like to know if /boot/efi a replacement for /boot mount point ? In my old non-UEFI machines, I used to create a dedicated 1GB partition (/dev/sda1) for /boot instead /boot being part / filesystem.

So, I would like to know if I still need to create a mount point for /boot (maybe /dev/sda2) . If /boot is obsolete in UEFI machines, I don’t have to do that.

Question2. Is it ok to create

/dev/sda1 —> for /boot/efi

and  /dev/sda2 ---> for /boot   ? 

Or the other way around ?

Question3. What exactly is stored in /boot/efi ?

Does ‘/boot/efi’ locate in Memory as ROM

I learned from the book Computer Science: An Overview that boot loader reside on Memory enter image description here

In a general-purpose computer, a program called the boot loader is perma- nently stored in the machine’s ROM. This, then, is the program that is initially executed when the machine is turned on. The instructions in the boot loader

However, in other book, it state that boot loader is located on hard disk

As for BIOS

the boot process begins with the BIOS. As described in Chapter 3, you tell the BIOS which boot device to use—a hard disk, a USB stick, a CD/DVD drive, or something else. Assuming that you pick a hard disk as the primary boot device (or if higher-priority devices aren’t bootable), the BIOS loads code from the Master Boot Record (MBR), which is the first sector on the hard disk.

enter image description here

for UEFI

In order to work, the EFI must know about the boot loaders installed on the hard disk’s ESP.

enter image description here

Put my question in another way

me@host:~$   df -h | grep 'boot' /dev/sda1       511M  7.3M  504M   2% /boot/efi 

Does the ‘/boot/efi` locates as ROM in Memery?

Does ‘/boot/efi’ locate in Memory as ROM

I learned from the book Computer Science: An Overview that boot loader reside on Memory enter image description here

In a general-purpose computer, a program called the boot loader is perma- nently stored in the machine’s ROM. This, then, is the program that is initially executed when the machine is turned on. The instructions in the boot loader

However, in other book, it state that boot loader is located on hard disk

As for BIOS

the boot process begins with the BIOS. As described in Chapter 3, you tell the BIOS which boot device to use—a hard disk, a USB stick, a CD/DVD drive, or something else. Assuming that you pick a hard disk as the primary boot device (or if higher-priority devices aren’t bootable), the BIOS loads code from the Master Boot Record (MBR), which is the first sector on the hard disk.

enter image description here

for UEFI

In order to work, the EFI must know about the boot loaders installed on the hard disk’s ESP.

enter image description here

Put my question in another way

me@host:~$   df -h | grep 'boot' /dev/sda1       511M  7.3M  504M   2% /boot/efi 

Does the ‘/boot/efi` locates as ROM in Memery?